Spark plugs for Johnson 115

[Matysiak]

I have got a 1980 115 Johnson running on NGK spark plugs. This forum isn't very complimentary about any other plugs than Champion.<br /><br />Should i change them to Champion plugs? What benefits will i get?<br /><br />Stephen

 

[WillyBWright]

Re: Spark plugs for Johnson 115

Go ahead and run them. Personally I prefer Japaneese plugs in Japaneese motors and American plugs in American motors. But NGK makes a fine sparkplug and will work just fine in that motor.

 

[Dhadley]

Re: Spark plugs for Johnson 115

Dont misunderstand -- there's nothing wrong with NGK plugs. The ignition on your motor was designed around a Champion plug and its characteristics. They are not necessairaly exactly the same as another brand.<br /><br />Sometimes the heat range is slightly off when going from one brand to another. You dont want to accidently go to a hotter plug and exceed the combustion parameters. If something suffers, most times its the piston(s).<br /><br />We do run NGK plugs in some carb'd race motors but we burn tremendous amounts of fuel too. Its all based off of combustion temps (EGT's). <br /><br />In a stock motor I'd sure stick with what the motor was designed for.

 

[seahorse5]

Re: Spark plugs for Johnson 115

If you are using the more expensive "Z" NGK plug with the correct heat range, you are OK. But if you are using the "R" or non R NGK, you should change to the correct Champion number, QL82C gapped to .030". Back before 1996, OMC recommended the QL77JC4, but changed the spec to a more foul-resistant plug.<br /><br />The Z in NGK and the Q in Champion indicate a suppressor type of sparkplug that the OMC ignition system needs. This is completely different from a resistor plug as it "retards" the AC current, but allows the DC current to pass thru unimpeded for the spark duration.

 

[marmon77]

Re: Spark plugs for Johnson 115

Hey guys, I posted a message, on the main board, but didn't get a reply . I was trying to get the correct plug for my "86" Johnson 150. I just purchased the boat and was going to start a maint. record to keep track of the hours on the plugs so my reason for replacing. The plugs that I pulled were QL77JC4 $ 2.49 I looked in the manuel at the store and it showed a different plug # (which I don't remember) but it cost $8.49. The store had a Clymers manuel so I thumbed thru there and it also gave a different plug # UL77V $4.79 I cross referenced it with NGK which showed BUHXW-1 $4.19. Clymers showed the QL77JC4 for "87" - "90" but not for the "86" model. I bought the NGK plugs because I like them it's what I run in all my jetski's plus they were half the price of the recommended Champion plug. Your thoughts and responses are greatly appreciated.

 

[walleyehed]

Re: Spark plugs for Johnson 115

My book shows UL77V as the prefered plug and QL16V as the alternate.....Beings I have the UL77V in my 82 200GT, I'd like to hear from DH or Seahorse on their thoughts on this as well.

 

[DJ]

Re: Spark plugs for Johnson 115

I'm not a huge fan of Champion plugs, However, Johnny/Rudes were designed with them (Champion) in mind and they do exhibit strange charactersics without them.<br /><br />Just my experience talking.

 

[marmon77]

Re: Spark plugs for Johnson 115

Got it Kenny from my other post. I just need to be alittle more patient, I guess, on waiting for a reply.

 

[marmon77]

Re: Spark plugs for Johnson 115

DJ, would you care to elaborate a little on "strange characteristics" ?

 

[DJ]

Re: Spark plugs for Johnson 115

M.A.<br /><br />I will. <br /><br />I've seen weird (read-hard) cold start characteristics all the way to burned pistons. Burned pistons due to plug depth, slightly "off" heat range, what have you.<br /><br />It's just my opinion that one should NOT deviate from what the the designers of the engine had in mind. Especially if those products (plugs) are still available.<br /><br />Again, I'm just talking from experience.<br /><br />If you are fouling plugs, or are having other symptoms, it's not the plugs, it's usually fuel delivery.

 

[Dhadley]

Re: Spark plugs for Johnson 115

I have seen exactly the same thing as DJ. <br /><br />Now, heres the other thing -- if you use a cross-over Champion in a Merc or Yamaha (that was designed around NGK) they can tend to cold foul or "wear out" real easy. Not all motors but some. Which means the Champions dont burn quite as hot as NGK. In this case all you do is cuss those stupid Champion plugs and go back to NGK. <br /><br />Given the possibility of the NGK burning hotter, and it gets into a Evin/John motor, bad things can happen under certain circumstances. Its very possible, I've seen it many times just like DJ said. In this case you cuss those stupid E/J motors as you change the pistons.<br /><br />So, this leads one to think that the crossover between Champion and NGK may not be all that of an absolute direct cross. If the NGK does indeed burn a bit hotter in the motor it was designed for it will obviously burn hotter in a different motor.<br /><br />BTW -- this isnt NGK bashing. We've seen damaged motors that had other non-Champion plugs. It has more to do with OE design than anything.

 

[marmon77]

Re: Spark plugs for Johnson 115

Point taken. I used the NGK's because the store I was in didn't have enough of the other. I'm not a die-hard NGK fan, jsut familiar with them because I use them in all my jet-skies. I'll get them changed out as soon as I can!